In his first-ever interview, the sole Australian survivor of the Waco siege has revealed to 60 Minutes what really took place during the 51-day stand-off, and why he believes crazed cult leader David Koresh will one day return to Earth as the son of God.

UK's Johnson sorry amid Iran aid stoush

British Foreign Secretary Boris Johnson has apologised for causing distress with remarks about a Iranian-British aid worker jailed in Iran.

Nazanin Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, was sentenced to five years after being convicted by an Iranian court of plotting to overthrow the Islamic Republic's clerical establishment. She denies the charges.

Johnson said on November 1 that she had been teaching people journalism before her arrest in April 2016, contradicting her and her employer, who said she had been on holiday visiting her family.

"Of course I apologise for the distress, for the suffering that has been caused by the impression I gave that I believed she was there in a professional capacity. She was there on holiday," Johnson told parliament on Monday.

"I do apologise. Of course I retract any suggestion she was there in a professional capacity."